This invention relates to a high-voltage variable resistor, and more particularly to a high-voltage variable resistor called a focusing pack which is used for adjusting a focusing voltage, a screen voltage or the like in a cathode ray tube (CRT) or the like.
In order that connection of a lead wire for connection between a high-voltage variable resistor and another component to an electrode on a substrate for a circuit (hereinafter referred to "circuit substrate") is carried out in a last step in assembling of the high-voltage variable resistor and a lead wire of a desired length is used for the connection, proposal is made for connecting a core of the lead wire to a terminal fitment fixed on the circuit substrate without soldering.
For example, Japanese Utility Model Application Laid-Open Publication No. 192601/1987 (62-192601) teaches, by way of example, a terminal fitment for electrically connecting a core of a lead wire to an electrode on a circuit substrate without soldering in a high-voltage variable resistor. The terminal fitment disclosed is connected at one end thereof to an electrode incorporated in a circuit pattern formed on a front surface of the circuit substrate and provided at the other end thereof with a core holding section including at least one edge element adapted to bite into an outer periphery of the core of the lead wire inserted thereinto. Unfortunately, the terminal fitment fails in an increase in the number of edge elements required for securely holding the core of the lead wire in the terminal fitment, because the edge element causes the terminal fitment to be complicated in structure. Also, the edge element is formed into an inverted triangle or V shape, resulting in having a pointed or sharpened distal end. An increase in the number of edge elements thus formed into an inverted V shape leads to a significant increase in configuration and dimension of the terminal fitment.
Japanese Utility Model Application Laid-Open Publication. No. 157075/1982 (Japanese Utility Model Application No. 73333/1980) and Japanese Utility Model Application Laid-Open Publication No. 130387/1983 (Japanese Utility Model Application No. 27255/1982) each disclose another terminal fitment for connection of a core of a lead wire thereto, which terminal fitment includes a single edge element adapted to bite into a core of a single lead wire and a spring for biasing the core of the lead wire against a wall of the terminal fitment. The terminal fitment has the disadvantage of failing to securely hold the core of the lead wire therein, to thereby be inconvenient for use for connection of a lead wire to which a high voltage is applied.
A further terminal fitment for connection of a core of a lead wire thereto is disclosed in Japanese Patent Application Laid-Open Publication No. 43371/1982 (Japanese Patent Application No. 50469/1981), which is provided with a single edge element adapted to bite into a core of a lead wire. The terminal fitment likewise fails to firmly hold the core of the lead wire therein, to thereby be unsuitable for use for connection of a lead wire to which a high voltage is applied.